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Alluvial Fan Flooding

NFIP Policy Index

• Definition/Description
• NFIP Requirement
• Guidance
• Related Keywords
• Special Topic Resources

Definition/Description

Flooding occurring on the surface of an alluvial fan or similar landform which originates at the apex and is characterized by high-velocity flows; active processes of erosion, sediment transport, and deposition; and unpredictable flowpaths. Alluvial fan flooding is depicted on a Flood Insurance Rate Map (FIRM) as Zone AO, with a flood depth and velocity.

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NFIP Requirement

•    59.1 - Definition

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Guidance

• IS-9 Managing Floodplain Development Through The National Flood Insurance Program (NFIP) (Page 1-14) and Regulatory Standards (page 6-28) (PDF 8MB, TXT 1MB) (entire document)
  
• CRS Commentary Supplement for Special Hazards Credit  

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Related Keywords

• Zone AO

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Special Topic Resources

• Guidelines for Determining Flood Hazards on Alluvial Fans

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Last Modified: Wednesday, 11-Aug-2010 14:30:40 EDT